Morphology Of Polyaniline Films Research Articles

An Aqueous Exfoliation of WO3 as a Route for Counterions Fabrication-Improved Photocatalyticand Capacitive Properties of Polyaniline/WO3Composite.

In this paper, we demonstrate a novel, electrochemical route of polyaniline/tungsten oxide (PANI)/WO3) film preparation. Polyaniline composite film was electrodeposited on the FTO (fluorine-doped tin oxide) substrate from the aqueous electrolyte that contained aniline (monomer) and exfoliated WO3 as a source of counter ions. The chemical nature of WO3 incorporated in the polyaniline matrix was investigated using X-ray photoelectron spectroscopy. SEM (scanning electron microscopy) showed the impact of WO3 presence on the morphology of polyaniline film. PANI/WO3 film was tested as an electrode material in an acidic electrolyte. Performed measurements showed the electroactivity of both components and enhanced electrochemical stability of PANI/WO3 in comparison with PANI/Cl. Thus, PANI/WO3 electrodes were utilized to construct the symmetric supercapacitors. The impact of capacitive and diffusion-controlled processes on the mechanism of electrical energy storage was quantitatively determined. Devices exhibited high electrochemical capacity of 135 mF cm−2 (180 F g−1) and satisfactory retention rate of 70% after 10,000 cycles. The electrochemical energy storage device exhibited 1075.6 W kg−1 of power density and 12.25 Wh kg−1 of energy density. We also investigated the photocatalytic performance of the deposited film. Photodegradation efficiencies of methylene blue and methyl orange using PANI/WO3 and PANI/Cl were compared. The mechanism of dye degradation using WO3-containing films was investigated in the presence of scavengers. Significantly higher efficiency of photodecomposition of dyes was achieved for composite films (84% and 86%) in comparison with PANI/Cl (32% and 39%) for methylene blue and methyl orange, respectively.

Morphology of polyaniline films on polyethylene terephthalate substrate

Morphology of polyaniline films on polyethylene terephthalate substrate

Decolorization of azo dyes by photo electro adsorption process using polyaniline coated electrode

This study is a report on the photo electro adsorption (PEA) decolorization of a mixture of three azo dyes, i.e., Acid Red 88 (AR88), Acid Blue 92 (AB92), and Acid Orange 2 (AO2) with polyaniline-modified electrode as a conductive polymer. Aniline was electropolymerized on steel electrode by being immersed in a solution containing HClO4 as the supporting electrolyte and NaClO4 as the dopant. This modified electrode was then used in a non-continuous reactor using UV irradiation for the decolorization of azo dyes. To obtain the best conditions for high decolorization efficiency, experiments were carried out at different operational conditions, including initial dye concentration, pH, and bias potential. The morphology of polyaniline film was analyzed by scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectrum was obtained to characterize polyaniline and dyes. Energy consumption was calculated to be 3.6kWh/m3 after 36min of treatment process. Maximum removal of 96% was achieved for the mixture of AR88, AB92, and AO2 in aqueous solution at pH 5, initial dye concentration of 30mgL−1, and bias potential of 1.3V after 40min of PEA process. The results indicate that the PEA process could be effectively applied to the removal of industrial effluents.

Electrochemical Synthesis of Sensitive Layer of Polyaniline: Effects of Acid Doping on Ethylene Gas Sensing

Ethylene gas is released from plants as a hormone during a certain stage of life cycle and induces ripeness in fruits and blooming of flowers. The early detection and control amount of ethylene gas in storage can prevent wastage of the entire stock. The aims of this research were to fabricate ethylene sensor based on polyaniline (PANi) and to investigate the effect of acid doping on an improvement of its sensitivity. Electrochemically synthesized conductive layer of PANi was prepared via an in situ radical polymerization by repeating potential cycling in the range of -0.3 to 1.0 V relative to the silver reference electrode and platinum counter electrode. The PANi films were deposited on interdigitated electrode of gold substrate. These emeraldine bases of PANi were doped with five different acids doping (such as HCl, H2SO4, H3PO4, TSA, and DBSA) at particular concentration. The influences of types and amount of acid on the sensitivity of acid doping PANi on ethylene gas were investigated. The PANi-dope films were characterized by Fourier transform infrared spectroscopy (FT-IR) and UV-visible spectroscopy (UV-vis). The morphology of PANi film was investigated by scanning electron microscope (SEM). The magnitude sensing of doping PANi in terms of types and amount of acid against ethylene gas was presented. Introduction

Electrochemical Synthesis of Polyaniline as Ethylene Gas Sensor

The aim of this work is to fabricate an ethylene gas sensor based on polyaniline (PANi). The conductive layer of emeraldine base PANi was prepared by electrochemical synthesis. The aqueous aniline solution in sulfuric acid was electrolyzed by repeating potential cycling between -0.4 and 1.0 V relative to the silver reference electrode and platinum counter electrode. The conductive layers of PANi were deposited on patterned interdigited gold substrate. The numbers of repeated potential cycles on the amount of deposited layers of PANi were investigated for ethylene gas detection. The morphology of PANi films was investigated by scanning electron microscope (SEM). The ethylene gas sensing of PANi-H2SO4 was evaluated based on the changes in conductivity of PANi-H2SO4. The results revealed that the magnitude sensing provided a good sensitivity against ethylene with concentration in the parts per million (ppm) ranges. The effect of amount of deposited layer of PANi on ethylene gas sensing will be presented.

INFLUENCE OF SCANNING MODES OF CYCLIC VOLTAMMETRY ON THE SURFACE MORPHOLOGY OF POLYANILINE FILMS

Polyaniline films on Ti-based metal substrates with granular,fibrillar and tube-slice surface morphology were prepared in a 0.2 mol·L~(-1) aniline solution in 0.5 mol·L~(-1) sulfuric acid by using the cyclic voltammetry method with scanning valtages in the range of-0.1 V～0.9 V at a scanning rate of 50 mV·s~(-1).The electrochemical properties and structure of polyaniline film electrodes were characterized by SEM,cyclic voltammetry(CV) and electrochemical impedance spectra(EIS).The result show that the different surface morphology of polyaniline films has different nucleation and growth mechanism,and polyaniline on Ti-based metal has prodigious surface area and good electrical conductivity.The tube-slice polyaniline has the least film impedance and the best electrical conductivity.

Doping of polyaniline by transition metal salts: effect of metal cation on the film morphology

Transition metal salts have been employed as dopants leading to conductive polyaniline (PANI) films. These dopants were found to be able to interact with polyaniline chains directly and to induce changes in morphology of polyaniline films, thus leading to the metal cation-induced processibility of these films. It was found two opposite tendencies of doping, resulting in formation of conductive films with different morphologies. The typical salts leading to these opposite tendencies are NiCl 2, EuCl 3, on the one hand, and ZnCl 2 on the other hand, respectively.

Preparation of Even Polyaniline Film on Magnesium Alloy by Pulse Potentiostatic Method

An even polyaniline film that adheres strongly to the magnesium alloy substrate has been prepared by pulse potentiostatic method in an alkaline solution. The film thickness was followed as a function of polymerization time. The film morphology and the bond strength between the polyaniline film and magnesium alloy substrate are deeply depended on the electrical parameters used in the preparation. The growth mechanism and the morphology of polyaniline film were analyzed by SEM. The infrared spectrum of the polyaninline film was also obtained.

Effect of annealing on electrical conductivity and morphology of polyaniline films

We report structure–property relationships of polyaniline emeraldine base (EB) films that were produced by combining different processing steps in various sequences. The effect of annealing and doping processes on the surface structure of the films was investigated by atomic force microscopy (AFM), and the corresponding changes to the chemical structure of the EB films were monitored by Fourier transform infrared spectroscopy. AFM results indicate that after doping polyaniline (EB) films with HCl, the root mean square (rms) roughness of the surface of EB film increased ∼ 46%. When the doped films were annealed at 180°C under a nitrogen atmosphere for 3 h, the rms roughness was essentially unchanged from that of the initial, undoped films. The electrical conductivity of the films also showed a significant dependence on the processing sequence. When the doped polyaniline (EB) films were annealed, no electrical conductivity was observed. When these films were redoped, only ∼ 6% of the initial conductivity could be recovered. In another processing sequence in which the polyaniline (EB) films were first annealed and then doped, the electrical conductivity was only ∼ 12% relative to the film that was doped immediately after being cast. From this work, a strategy to reduce the surface roughness of films made from electrically conducting polyaniline (EB) is proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3602–3610, 2001

Effect of annealing on electrical conductivity and morphology of polyaniline films

AbstractWe report structure–property relationships of polyaniline emeraldine base (EB) films that were produced by combining different processing steps in various sequences. The effect of annealing and doping processes on the surface structure of the films was investigated by atomic force microscopy (AFM), and the corresponding changes to the chemical structure of the EB films were monitored by Fourier transform infrared spectroscopy. AFM results indicate that after doping polyaniline (EB) films with HCl, the root mean square (rms) roughness of the surface of EB film increased ∼ 46%. When the doped films were annealed at 180°C under a nitrogen atmosphere for 3 h, the rms roughness was essentially unchanged from that of the initial, undoped films. The electrical conductivity of the films also showed a significant dependence on the processing sequence. When the doped polyaniline (EB) films were annealed, no electrical conductivity was observed. When these films were redoped, only ∼ 6% of the initial conductivity could be recovered. In another processing sequence in which the polyaniline (EB) films were first annealed and then doped, the electrical conductivity was only ∼ 12% relative to the film that was doped immediately after being cast. From this work, a strategy to reduce the surface roughness of films made from electrically conducting polyaniline (EB) is proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3602–3610, 2001